The invention relates to the manufacture of brooms, brushes and similar articles utilized for household or general sweeping and cleaning.
Conventional manufacture of such cleaning aids, at industrial level, envisages the embodiment of a solid back which carries small bunches either of natural bristles or of synthetic fibers, known as tufts, and permits of attaching a staff or handle for ultimate use, by hand, of the finished article.
Such backs are generally flat, though in some embodiments may either exhibit curved or bent-upward longitudinal ends, or be curved through their entire length, as illustrated in FIGS. 1, 2 and 3, and are provided with stopped holes distributed uniformly over the surface opposite that to which the handle is attached.
The holes thus produced accommodate tufts of fibers. Such fibers, of a given selected type, are bunched together into small bundles approximately twice the length X (FIG. 1) of the formed tuft which ultimately projects from the back of the finished broomhead, the bundle of fibers being bent double into a U thereby providing a fold by means of which to facilitate insertion of the tuft into a corresponding hole offered by the back. Drilling of holes in the back and insertion of the tufts therein are operations accomplished by locating the back in a three-dimensional pantograph-type copying jig which permits movement about a fulcrum coincident with the axis passing through the center of the back, and located at a point distanced from the side to which the handle is ultimately attached. In this way it becomes possible to produce holes in the solid back that are angled with respect to the surface from which the tufts project, in such a way as to fan out the pattern of the tufts, at least toward the outer ends of the back.
Such fanning-out of the tuft pattern performs two functions: first, that of increasing the overall length of contact L between the fibers and the surface to be swept, in relation to the length of the back; and second, that of permitting access to tight corners and skirtings when sweeping, without any obstruction from the back of the broomhead itself.
The prior art makes provision, when utilizing flat backs of the type illustrated in FIG. 1, either for rounding-off or beveling the ends, which permits only a limited fan-out of the tuft pattern however, as maneuver of the back relative to the tool during drilling is possible only in a very limited measure. The drill bits are in fact unable to penetrate a surface sharply angled relative to their own axis, and must be safeguarded from the risk of breakage caused through excessive bending stress. The result is that the distance D between the outermost ends of the back and the tips of the outer tufts (which project from the outermost ends of the back) is often insufficient to ensure that the back of the broomhead will not itself constitute an obstruction to efficient sweeping of tight corners and skirtings.
In an attempt to improve the situation thus described, use has been made of backs as illustrated in FIGS. 2 and 3 of the drawings. In these instances however, the overall length of contact L between the fibers and the surface to be swept is shortened, by reason of the fact that the tips of the outer tufts are raised from the surface on which tufts located along the middle section of the back come to rest. At all events, the distance D between the outermost ends of the back and the tips of the outer tufts is barely greater than the distance D as illustrated in FIG. 1, and as such, is insufficient to provide an effective solution to the problem of sweeping tight corners and skirtings.
Studying the type of relative movement with which a brush or broom back is usually invested when drilling holes and subsequently inserting the tufts (bristle or synthetic fiber), the applicant observes that, were the back to be provided with a series of flat, concave or convex angled surfaces, along the longitudinal stretches nearest the outermost ends at least, such as will offer points of contact lying at right angles to the drill-bits and tufting tools in any given location, it would be possible to embody a broomhead, for example, wherein the tufts projecting from the solid back could be fanned out to a notable degree. Furthermore, the applicant observes that by inserting tufts of greater length into these holes located near the outermost ends of the back, than those inserted into the uniformly-distributed holes of the middle section, one obtains a broomhead which in addition to exhibiting a notably fanned-out tuft pattern, is embodied such that the tips of all the tufted bristles or fibers may lie within a common plane. The combined effect of these two techniques would be such as to permit embodiment of a broom capable of affording the optimum solution to those problems described above.